Maximum Intensity Projection (MIP) is a method for displaying a three-dimensional image with a medical image diagnostic apparatus. In the MIP method, a line of vision is considered that corresponds to each pixel constituting an image (MIP image) the operator is attempting to obtain as a result, and by taking the maximum values among luminances of pixels present on the line of vision in volume data of a target object as the luminance values of pixels corresponding to the MIP image, an MIP image which three-dimensionally displays image data obtained from the target object is obtained.